Pseudopegolettia H. Rob., Skvarla & V.A. Funk, 2016

Robinson, Harold, Skvarla, John J. & Funk, Vicki A., 2016, Vernonieae (Asteraceae) of southern Africa: A generic disposition of the species and a study of their pollen, PhytoKeys 60, pp. 49-126 : 91

Pseudopegolettia H. Rob., Skvarla & V.A. Funk gen. nov. Figures 23 A–E ; 24 A–H

Type.

Pegolettia tenella DC.

Descriptions.

Small perennial herbs; stems erect, with short branchlets from lower nodes, puberulous to subsericeous with short-stalked hairs bearing asymmetric cap cells, stalks moderately broad with one or two septae, cap cells short and stout, attached near lower end. Leaves alternate, oblong to linear, essentially sessile, sparsely puberulous, abaxially densely glandular punctate. Inflorescence terminal with 1 or a few heads borne on long peduncles. Heads campanulate, 1.7-2.5 cm. wide; involucral bracts 20-60, in ca. three series, subequal, linear-lanceolate, herbaceous with slender tips, pilosulous outside; receptacle slightly convex, surface with angular thickenings. Florets 15 or more in a head; corollas purple, ca. 1 cm long, narrowly funnel-shaped from a slender base, throat slightly shorter than the moderately distorted, linear-lanceolate lobes, outer surface with short glands on tube and throat, spiculiferous distally on lobes; anther thecae narrowed at base to short lobulate tail; apical appendage glabrous, ovate with rather firm cell walls; style base with narrow annular node; sweeping hairs acicular, restricted mostly to style branches, few on upper shaft. Achenes mostly 6-8-ribbed, to 4.5 mm long, with glandular punctations and scattered idioblasts on sides, rarely without or with many short setulae that are not or scarcely split at apex, inner layer without raphids or with subquadrate raphids, with layer of rather sclerified narrow cells appearing as striations under the glands and idioblasts; carpopodium broadly stopper-shaped, sometimes with few short uniseriate hairs on inner surface; pappus of ca. 40 scabrid bristles, mostly in one series, as long as tube and throat of corolla, rather easily deciduous, scarcely narrowed except at tips, with few indistinct short bristles in outer series. Chromosome number unknown.

Pollen ca. 47 μm in diam., tricolporate, sublophate, echinate, with perforated tectum continuous between colpi (Fig. 24 A–H ).

Most notable secondary metabolites include sesquiterpene glaucolides ( Bohlmann and Jakupovic 1990 as Vernonia monocephala Harv.) and 5-alkylcoumarins ( Bohlmann and Jakupovic 1990 as Vernonia galpinii Klatt).

The genus consists of mostly monocephalous species, but those species have many individual differences such as the restriction of leaves to a basal rosette, capitula structure, and pubescence of the achenes. They do have essentially identical pollen, but it is a widely distributed pollen type in the Erlangeinae . There are no unique or uncommon characteristics that the two species share.

Figures

Figure 23. Photographs of Pseudopegolettia and Vernoniastrum: A-C Pseudopegolettia tenella (DC.) H. Rob., D-E Pseudopegolettia thodei (Phillips) H. Rob., Skvarla & V. A. Funk, note: images show the leafy stem of Pseudopegolettia tenella and the succulent basal leaves of Pseudopegolettia thodei; F-G Vernoniastrum latifolium (Steetz in Peters) H. Rob .. See Appendix C for citation details.

Figure 24. Scanning electron micrographs of Pseudopegolettia. A-H Scanning electron micrographs of acetolyzed sublophate-echinolophate pollen of Pseudopegolettia tenella (DC.) H. Rob. A Polar view B Equatorial view with prominent lophal ridges surrounding pore C Lateral view D Polar view, slightly different from A E Equatorial view F Lateral view slightly different from C G and H are fractured grains showing the thickened and distally bifurcated support columellae for the overlying exine. From Sidley 3904.